Sensors are commonly used to capture some physical quantity, like temperature, magnetic field, electric current, electric voltage, pressure, etc., and to output an electric signal (e.g., voltage signal or current signal) corresponding to the captured physical quantity. Besides the actual sensor, sensor devices may comprise additional components like amplifiers, voltage references or analog-to-digital converters (ADCs) to process the signals generated by the actual sensors. Such sensor devices may, for example, be integrated on a single chip.
Sensor devices may be used in safety-critical applications, for example in the automotive environment. For example, in the automotive field airbag deployment or antilock braking systems (ABS) may operate based on signals received from sensor devices. For such safety-critical applications, various requirements exist for sensor devices and systems using such sensor devices. For example, in the automotive field International Organization for Standardization (ISO) 26262 defines functional safety requirements for road vehicles.
One requirement which may often exist in such safety-critical applications is that malfunctions of the sensor device have to be detectable by the system, for example by an entity receiving signals from the sensor device. In other words, according to such a requirement it has to be possible to detect, if a sensor device delivers erroneous values, e.g. due to a fault of the sensor device. One approach to ensure this is to provide redundancy, for example to provide two separate sensors for measuring the same physical quantity. Deviations between measurements of the two sensor devices above a threshold may indicate a malfunction of at least one of the two sensors provided. However, providing such redundancy requires additional chip space.
As a related problem, as manufacturers need to guarantee adherence to safety requirements, manufacturers may want to ensure that only components approved by them are used, for example in the case of a replacement of components like sensor devices. In this case, it may for example be desirable to be able to detect whether a replacement component from the original manufacturer or a different replacement component is used.
Therefore, a general need exists to be able to obtain information about a sensor device, for example regarding possible malfunction of the sensor device or regarding authenticity of the sensor device, in an efficient manner.